A heated battle that spread to federal courtrooms and the U.S. Congress ended on Tuesday with the U.S. Air Force clearing Elon Musk’s rocket company SpaceX to fly military and national security satellites.

The unmanned X-37B spacecraft is scheduled to blast off atop a United Launch Alliance Atlas V rocket from Florida's Cape Canaveral Air Force Station, during a four-hour launch window that opens at 10:45 a.m. EDT.